armymech666

Car has sat for a couple years but only has 29,000 miles. Just borrowed it from my sister and drove it home last night but it progressively got worse. It is basically sucking excess air in through the air filter. It idles high and when you come to a stop, the idle cuts down hard and almost stalls... sometimes it does. It idles rough. Has fault codes 33 and 42. I replaced the IAV (idle air valve) so far but don't have much money to throw at it. I am guessing maybe the TPS or the MAP is bad? But the condition for code 33 is that it is not throwing a code for the TPS. Could the TPS still be bad though?

I reset ECU, main problem is that the SES light comes on right away even after reset. This happened before i changed IAC change as well. I did run some seafoam through a vacuum line and i drove it for about 5 minutes and it fixed the problem. But it came back when I restarted it. Whatever it is is causing the engine to $uck in way too much air. I can literally hear it sucking from in the car. But it is definitely coming from the air filter.

armymech666

Today I rechecked the IAV and it is all good. I ran some more seafoam through it and nothing happened. I checked all plugs and they are good. I cleared the codes and rechecked. It only gave me code 42 this time. So it is something between the crank sensor, ICM and coils. Not really sure where to go from here, everything looks like a pain to get to.

GHOSTOWLGRID

Check all vacuum lines and make sure that they are not cracking/damaged.

33 is improper manifold pressure, chances are there is a leak somewhere.
which means your dumping extra gas to compensate.
if you have the old 3.1L MPFI v6 like I did, my vacuum lines got brittle after 20 years and cracked, had similar issues...
The I4, do the same, check all vacuum lines.

code 42 is spark timing, try replacing the spark plugs, they might be fouled.
Check the spark wires if they are old, they can leak to ground.

How is it acting now?
What engine you got?